Development Of Harrow Suction Dredger Dynamic Positioning Semi-physical Simulation Platform

The dynamic positioning of harrow suction dredger means that the harrow suction dredger can resist the external force disturbance from the Marine environment and its own internal disturbance by relying on the thrust action of its own propeller,so that the hull can keep a certain attitude in a certain position at sea or sail along a certain set course.In order to ensure the high efficiency and safety of Marine operation,the dynamic positioning system is an important equipment for the rake suction dredger to realize Marine operation.Because it is difficult to detect the performance of dynamic positioning system in real ship application,and the test cost is high.In view of this situation,this thesis carries out the research on the semi-physical simulation platform of the dynamic positioning of the rake suction dredger,which can effectively reduce the limitation and risk of the real ship test.This thesis takes a large rake suction dredger as the object to analyze and study the dynamic positioning control functions and effects under different environments and working conditions.The main work is as follows:(1)The motion characteristics of the rake suction dredger operating at sea and the influence of wind,wave and current interference on the rake suction dredger in the Marine environment are analyzed.The model of the rake suction dredger sailing and dredging at sea is correctly modeled,and the ship model satisfying the controller control requirements and the similar complexity of the real ship is established.This thesis studies the drag force of the rake arm in the seabed during dredging and establishes a mathematical model based on it.The mathematical model for dredging process of rake suction dredger is established,which lays the foundation for dynamic positioning control research.(2)Aiming at the problems of high frequency interference of external force and thrust distribution of rake suction dredger at sea,the improved Kalman filter and thrust optimal distribution strategy are designed respectively.A PID controller based on particle swarm optimization(PSO)was designed to solve the problem of the control performance of the dynamic positioning controller of the rake suction dredger in offshore operation.Particle swarm optimization PID controller is easy to fall into local optimal.An improved particle swarm optimization method is designed to improve the particle search performance and optimization efficiency,and improve the control accuracy of the controller.The traditional optimization algorithm and the improved optimization algorithm were simulated and verified by MATLAB.The simulation results show that the improved particle swarm optimization method has higher accuracy and better stability.(3)By analyzing the overall framework of the semi-physical simulation platform and combining with the dynamic positioning control workflow,the composition of the dynamic positioning semi-physical simulation system is determined.The harrow suction dredger kinematics model and improved particle swarm optimization controller were added into the harrow suction dredger simulation platform to carry out the harrow suction dredger simulation test.The test results show that the designed harrow suction dredger dynamic positioning controller is effective,and can realize the performance test of harrow suction dredger dynamic positioning controller under different sea conditions and working conditions.